Known methods for producing sintered products having complicated three-dimensional shapes include a process which comprises injection-molding a kneaded mixture comprising a powder and a binder, taking the molded product out of the mold, and sintering the molding after debindering.
Accordingly, the aforementioned process comprises a step of releasing the molded product from the mold, and this conventionally was done (1) manually, i.e., by hand or (2) using a robot, by either mechanically chucking the sprue of the molding, or holding the molding with a pad using an adsorptive force exerted by reducing pressure.
Those methods, however, each have their own disadvantages; a manual step is always a hindrance in scaling up production. The use of robots may possibly improve productivity, but in the former, it often was the case that the molded product which was still not sufficiently strong at the gate caused breakage to occur, and thereby the molding would drop off. Thus, this method suffered low yield. The later also comprises various problems, such as occasional fall off of the molding ascribed to the insufficient adsorptive force of the pad not withstanding the weight of the molding having high specific gravity; inapplicability to the moldings having curved faces where a tight contact between the molding and the pad is not achievable, or to the moldings having through holes, where the reduced pressure cannot be maintained; and a time- and power-consuming positioning of the pad at high precision to achieve effective function of the pad.